Driving tool for tubular grounding rods



Feb. 21, 1939. f Q DANlELS 2,147,829

DRIVING TOOL FOR TUBULAR GROUNDING RODS Filed March ll, 1938 Patented Feb. 21, 1939 UNITED STATES PATENT OFFICE DRIVING TOOL FOR '(ISUBULAR GROUNDING R DS Application March 11, 1938, Serial No. 195,323

7 Claims.

The present invention relates to an improvement in driving-tools for tubular grounding-rods constructed of relatively-softer metals such, for example, as copper, which have a high degree oi electrical conductivity and are superior for making and maintaining grounding-contacts.

The general object of this invention is to provide a driving-tool of improved construction which will facilitate the driving of soft-metal grounding-rods and thus render more available the superior electrical-conducting and groundcontacting qualities of these metals.

One of the objects of the present invention is to provide suitable and effective means to protect the upper end of a tubular grounding-rod constructed of relatively-soft metal, from deformation and mutilation, when said grounding-rod is driven under the recurring impacts of a driving-tool which embodies the protective means.

Another object of the invention is to maintain the predetermined size and shape of the tubular grounding-rod at its upper end during recurring impacts thereon by a driving-tool for the purpose of facilitating the subsequent attachment thereto of a wire-grounding cap or plug for electrical installations of various kinds.

With the above and other objects in view, as will appear to those skilled in the art, from the present disclosure, this invention includes all features in the said disclosure which are novel over the prior art.

In the accompanying drawing:

Fig. 1 is a side elevation of the driving-tool constructed according to the invention;

Fig. 2 is a .side elevation of a tubular grounding-rod after it has been completely driven by the driving-tool, and a wire-grounding plug or cap attached thereto at the top;

Fig. 3 is an enlarged side elevation of the 40 driving-tool shown in position on a tubular grounding-rod at the conclusion of the driving operation, the lower portion of the driving-head and the upper portion of the grounding-rod, being shown in section;

45 Fig. 4 is a transverse section on the line 4 4 of Fig. 3 as seen from below;

Fig. 5 is an enlarged side elevation of the driving-tool with the lower portion of the drivinghead broken away and shown in section; `and Fig. 6 is a transverse section on the line 6-6 of Fig. 5 as seen from below.

According to the embodiment shown on the drawing, the invention is illustrated in connection with a tubular grounding-rod I 0 of the character shown, described and claimed in the co- (Cl. (il- 73) pending application of GeorgeA.Hornbecker, led March l2, 1938, under Serial No. 194,454, which may be constructed of thin-walled hard-drawn copper tubing and provided at the bottom with a rigidly-attached leading-point*l II of conical form. The tubular member I0 may vary greatly with respect to length, diameter and wall-thickness, depending upon local conditions surrounding any particular installation. Such a tubular member may vary in length from about two feet m to eight or more feet and may vary in external diameter from about one-half inch to about one and one-quarter inch. The wall-thickness of said tubular member is preferably within the range of .025 inch to .035 inch approximately, for the purpose of providing maximum surface area for contact with the ground and at the same time for minimizing the amount of copper, or other relatively-expensive metal, required for a given installation.

While the driving-tool forming the subjectmatter of the present invention, may be utilized for driving a tubular grounding-rod with or without a contained ller-medium, in the form shown on the drawing, the tubular grounding- 9 rod shown is provided with a ller-medium comd prising superposed sections I2 of hard wood having a .sufhcient degree of resilience to eiectively support the tubular wall of the groundingrod,said ller-medium being preferably compressible axial- 1y and expansible in transverse cross-section into substantially-rigid engagement with the inner wall of the tube. According to Fig. 3, the driving-tool has been illustrated at the conclusion .of a driving-operation, the ller-sections having been axially-compressed and transversely-expanded to form a .consolidated core organized with and forming a permanent part of the grounding-rod assembly. As shown best in Fig. 5, a reciprocatory driving-head I3 with which the driving-tool is provided, has a central cylindrical cavity which defines the outer cylindrical wall of an annular recess vor driving-socket I4 having an inner end-wall or annular shoulder I5 whereby the recurring impacts of driving-head i3 are delivered to the upper end of the tubular grounding-rod. For the purpose of mounting a plunger-rod in the driving-head, the latter provided with an axial socket I6 which extends upwardly from annular shoulder I 5. Said plunger-rod comprises a portion Il of relatively-larger diameter secured within the socket I6 with a shrinking-nt, a portion I8 of relatively-smaller diameter which is reciprocable within the upper end of the tubular grounding-rod, and a short pose, the plunger-rod portion tapered portion I9 intervening between the portions il and I8. The portion II of the plungerrod defines the inner wall of driving-socket I4 and is sized to slidably fit the inner wall of the tubular grounding-rod which is slidably engaged on its outer wall by the outer cylindrical wall of driving-socket I4.

From the foregoing description, it will be understood that during the recurring impacts of the Vdriving-head I3 on the upper end of the tubular grounding-rod, the cylindrical walls of driving-socket le reciprocably engage the inner and outer tubular walls of the grounding-rodV in such a way as to protect and reenforce them against deformation or mutilation which, otherwise, they would be subjected to. When the driving-head I3 is reciprocated by hand, the upper end of the tubular grounding-rod I!) is frequently retracted from the driving-socket I4. During a subsequent downward movement of said driving-head, the upper end of groundingrod IQ strikes the tapered surface I9 which operates as a guide on the inner bore of the grounding-rod to register the upper end of the grounding-rod with respect to the driving-socket I wherein it is firmly supported andreenforced for the impact thereon of shoulder I5.' For' this pur- I'I is extended somewhat below the outer end of driving-socket I4 to eiect a proper registry of the tubular upper end of the grounding-rod i by the tapered surface I9 before the upper end of the groundingrod enters the driving-socket I4. To further facilitate this action, the driving-head is provided with a chamfered corner 2D extending around the aperture of the driving-socket I4. By means of the vchamferedv corner 2D, slight irregularities in contour may be corrected in the wall of the tubular grounding-rod as the upper end thereof is guided into the driving-socket. The reciprocatory driving-head I3 is preferably constructed of tool steel and in the event that it is desired to employ a driving-Sledge thereon, said driving-head is tempered to withstand the blows of the sledge.

Asl shown in Fig. 2, the leading-point II is preferably provided with Ya shank I2a which is driven into the lower end of tubular groundingrod I, the upper end of said shank serving as an anvil to receive recurring impacts directly transmitted thereto bythe plunger-rod portion I8 when the driving-tool which forms the subject-matter of the present invention is employed in place of that shown and described in my co-pending application Serial No. 150,988, iiled June 29, 1937. In this case, the plunger-rod of the driving-tool disclosed in the present application, is preferably constructed to serve the functions of the driving-plunger as described in the above-identified co-pending application while at the same time constraining the reciprocatory movements of the plunger-rod in the manner pointed out in the present case.

In many places, where the ground is relatively soft and of even texture, the tubular groundingrod with or without a reenforcingvcore therein,

may be sunk into the ground by a hand-reciprccation of a driving-tool constructed in accordance with the present invention. In other cases, where the ground is somewhat harder or denser Y and a grounding-rod provided with a consolidated core is preferably employed, the grounding-rod may be completely driven by the handmanipulation of driving-head I3 or by means of a` sledge for delivering recurring impacts upon the inner core of the grounding-rod through the plunger-rod without the annular shoulder I coming into engagement with the upper end of the grounding-rod. In other cases, where the ground is unusually resistant and renders it desirable to use a grounding-rod provided with a consolidated core, said grounding-rod may be driven at rlrst by means of impacts on the core within the grounding-rod and subsequently by means of a hand-operated or Sledge-driven action of the driving-head I3 to engage its shoulder I5 with the top of the grounding-rod. From the foregoing description, it will be understood that in unusuallyresistant ground, a driving-tool of improved construction according to the present application may be employed in connection with a tubular grounding-rod of the character disclosed in the above-identified applicatioin of George A, Hornbecker. By means of this combination of devices, the driving operation may be carried on in suchA a way as to include, at rst, the driving impacts delivered to the conical leading-point at the bottom through the core l2, which is materially reenforced and aided by an increased frictional engagement between the condensed core and the inner wall of the tubular grounding-rod, followed by recurring impacts of the driving-head I3 at the top of the tubular grounding-rod. In this way, exceedingly ei'ec- Ytive results may be obtained in driving tubular grounding-rods constructed of relatively-soit metal reeniorced and operated upon in the manner described above.

The invention may be carried out in other specific ways than those herein set forth, without departing from the spirit and essential characteristics of the invention, and the present embodimentsare, therefore, to Vbe considered in all respects as illustrative and not restrictive, and all changes coming within the meaning and equivalency range of the appended claims are intended to be embraced therein.

1. A driving-tool for tubular grounding-rods,

comprising: a plunger-rod to reciprocate within thetubular grounding-rod, and a driving-head mounted on the upper end of said plunger-rod, said driving-tool being provided with an annular recess within the driving-head and concentric tothe plunger-rod to receive the upper end oi said tubular grounding-rod.

2. A driving-tool for tubular grounding-rods, comprising: a driving-head provided with a cylindrical cavity having a circular wall to slidably lit the exterior wall of a tubular grounding-rod; and a plunger-rod mounted in said driving-head and concentrically arranged with respect to said cylindrical cavity, said plunger-rod having a portion disposed within said cylindrical cavity of suitable diameter to slidably t the inner wall of the tubular grounding-rod.

3. In a driving tool for tubular grounding-rods, a plunger-rod comprising a portion to slidably fit the bore of a tubular grounding-rod and a portion to deliver a driving impact within said grounding-rod; and a driving-head mounted on the upper end of 4said plunger-rod; said drivinghead being provided with a central bore provided with a transverse end-wall constructed and arranged to impinge upon the upper end of said tubular grounding-rod. Y

4; A driving-tool for tubular grounding-rods, saidV driving-tool comprising a driving-head and a plunger-rod, said driving-tool' being provided within the driving-head with an annular recesshaving circular walls to slidably t the inner and outer Walls of a tubular grounding-rod and a transverse Wall at the inner end of said annular recess to impinge upon the upper end of the tubular Wall of said grounding-rod; and the said plunger-rod projecting from said driving-head in concentric arrangement with said annular recess, said plunger-rod being provided with a tapered portion adjacent to' the outer end of said annular recess to center said upper end of the tubular Wall therein.

5. In a driving-tool for tubular groundingrods, a plunger-rod comprising a portion of relatively-larger diameter to slidably t the bore of a tubular grounding-rod and a portion of relatively-smaller diameter to impinge upon a part organized with and forming a permanent part of a tubular grounding-rod within the interior thereof; and a driving-head provided with a central bore having a circular Wall to slidably t the outer wall of said tubular grounding-rod and forming with the exterior of said relatively-larger portion of the plunger-rod, an annular socket to receive the end of said tubular grounding-rod, said annular socket being provided with an inner end-wall to impinge upon the upper end of the tubular grounding-rod while the inner and outer Walls thereof are supportably engaged by the circular Walls of said annular recess.

6. In a driving-tool for tubular grounding-rods,

a driving-head provided with a cylindrical cavity at one end having a circular wall to slidably t the outer wall of a tubular grounding-rod; a plunger-rod projecting outwardly from the inner end-wall of said cylindrical cavity and having a portion within said cavity to slidably lit the inner wall of said tubular grounding-rod, said plungerrod being provided with a lower-end portion to reciprocate Within the grounding-rod and an intermediate tapered guide portion interposed between the aforesaid portion to slidably t the inner wall of said tubular grounding-rod and said lower-end portion.

7. In a driving-tool for tubular grounding-rods, the combination with a reciprocatory drivinghead provided with a cylindrical cavity having a circular Wall to slidably fit the exterior surface of a tubular grounding-rod and with an annular shoulder arranged to deliver recurring impacts to the end of said grounding-rod, of a plunger-rod comprising a portion of relatively-larger diameter to slidably lit the interior surface of the tubular grounding-rod and disposed within said cylindrical cavity in concentric relation thereto; a portion of relatively-smaller diameter to reciprocate within the tubular grounding-rod; and an intervening tapered portion for slidably engaging the inner bore of the grounding-rod to guide the upper end thereof onto the said portion of relatively-larger diameter, said portion of larger diameter forming with the cylindrical wall of said cavity an annular driving-socket which reciprocably houses the inner and outer surfaces of the upper end of said tubular grounding-rod during recurring impacts of said shoulder on the upper end thereof.

HAROLD C. DANIELS. 

